Dual cell-high speed uplink packet access (DC-HSUPA) was introduced in Release 9 of the Third Generation Partnership Project (3GPP) specifications. DC-HSUPA introduced a secondary uplink frequency that a mobile terminal may utilize in order to perform uplink data transmission in addition to the primary uplink frequency. Along with the definition of the DC-HSUPA feature by Release 9 of the 3GPP specifications, event-triggered intra-frequency measurements were introduced for the downlink frequency associated with the secondary uplink frequency. However, the 3GPP specifications have not specified any technique for performing periodic measurements for a specific frequency, such as for the downlink frequency associated with the secondary uplink frequency, and for reporting the results of any such periodic measurements. Instead, the only intra-frequency measurements for the downlink frequency associated with the secondary uplink frequency are event-triggered intra-frequency measurements as opposed to periodic measurements.
TS25.331 of the 3GPP specifications defines an inter-frequency periodic measurement. If the periodic inter-frequency measurements are configured, the mobile terminal shall perform the periodic measurements on the configured inter-frequencies' neighbor cells in the neighbor cell list with the network being able to configure up to two inter-frequencies' neighbor cells in the neighbor cell list. However, these periodic measurements apply not only for a specific single frequency, but for all the configured inter-frequencies to be measured.